Mash-terpiece
One issue with getting birds to eat a healthier diet is that many birds enjoy a variety over something that appears plain and dull. I've noticed this especially with my own flock. A dish of cooked rice or a couple of pieces of vegetables can appear quite "boring" to the eye and not very interesting. Making up a batch of mash can intrigue those birds who love variety! A base mash diet consists of 30% grains, 15% legumes, 45% vegetables, and 10% fruits. The grains can be fed cooked or sprouted with the legumes cooked or sprouted with at least 1/4" tails. If using the larger legumes, be sure to fully cook these.
Do not sprout large beans due to the toxins not fully released when sprouting. Most vegetables can be fed raw or steamed, or you can even choose to use frozen vegetables. Be sure to steam potatos if you feed any. Fresh, organic fruits are best, although frozen fruits can be used as an alternative.
Cook or sprout the grains and legumes separately. For your smaller birds, you may want to chop up the legumes. Vegetables can be chopped finely, diced, sliced, julienned, chopped into chunks, or even run through the food processor. Fruits can be chopped or sliced. Once all the ingredients are prepaired, mix them together. Feed to your birds first thing in the morning and leave inside the cage for 2-6 hours, shorter periods of time if you have to deal with heat and humidity.
Your birds may ignore the mash for a day or two, but most birds will try the mash after a few days due to the variety of foods. You can help entice them to eat the mash by mixing in a small amount of seeds or sprouts.